1. Field of Application
The following description relates generally to telecommunications systems and wireless communications systems.
2. Prior Art
Cell capacity is a key performance measure in wireless cellular networks. Next generation of cellular standard, long-term evolution, advanced (LTE-A), has adopted many capacity-enhancing technologies, including coordinated multi-point transmission/reception (CoMP), multi-user multi-input multi-output (MU-MIMO), and heterogeneous networks (HetNet). Together these technologies have the potential to improve the cell capacity by many folds.
Successful implementation of the capacity-enhancing technologies in cellular networks, however, faces tremendous challenges. There are strong interferences between standard macro cells and the small HetNet cells. Interferences can also be severe between beams in MU-MIMO. Existing means to overcome or mitigate these challenges may significantly offset the benefits of the capacity-enhancing technologies. For example, one way to reduce the interference is to schedule the interfering transmission antennas or base stations to transmit on different resources in the manners of time multiplexing and frequency multiplexing, etc. However, resource multiplexing reduces the cell capacity considerably. CoMP is another way to reduce the interferences, but the channel feedback overhead of CoMP may overwhelm the uplink due to more and more transmitting antennas deployed in a macro cell for MU-MIMO.
Small HetNet cells also need backhaul connections to communicate with the macro cell and the network, which increases the deployment cost. The distributive nature of small HetNet cells also makes the centralized control of the cellular networks more difficult.
Thus methods, apparatus, and systems are needed that overcome the implementation challenges and that fully realize the benefits of the capacity-enhancing technologies.